Fetch API cannot load https://api.myapi.com/v2/licenses/verify/. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://mysite.com' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

Also Ive tried setting the request header itself in Construct before the request gets made...but that still gives me the error.

CORS needs to be set up on the server you are requesting data from, not from the construct app or the domain hosting the construct app. It is set in the hosting server's configuration files.

Are you sure? Because when I disable cors locally on my browser, the data gets retrieved from the source successfully. This would indicate that the data provider is sending the message anyway and its my construct hosted server that is not able to receive it (or send the request) correctly.

Even if you send a no-cors request, an opaque response cannot be read or accessed by JavaScript.

This is normal behavior, basically one use case is to prevent hot-linking to resources that are not yours (stealing bandwidth). Either you have access to the server/domain where the resource is hosted and configure it to allow cors, or you'll need a copy of the resource on the same domain as your game/app so then cors is not necessary at all.